An informal Economy

An informal economy is economic activity that is neither taxed nor monitored by a government, contrasted with a formal economy. The informal economy is thus not included in that government's Gross National Product (GNP). Although the informal economy is often associated with developing countries, all economic systems contain an informal economy in some proportion.
Informal economic activity is a dynamic process which includes many aspects of economic and social theory including exchange, regulation, and enforcement. By its nature, it is necessarily difficult to observe study, define, and measure. No single source readily or authoritatively defines informal economy as a unit of study.
The terms "under the table" and "off the books" typically refer to this type of economy. The term black market refers to a specific subset of the informal economy. The term "informal sector" was used in many earlier studies, and has been mostly replaced in more recent studies which use the newer term.

Micro economics are focused on an individual person in a given economic society and Macro economics is looking at an economy as a whole. (Town, city, region)